package com.mobile.framework.image;

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

public class ImageServlet extends HttpServlet {

    public static String SESSION4RAND;

    public static String SESSION_LOGINAJAX;

    /**
	 * Constructor of the object.
	 */
	public ImageServlet() {
		super();
	}

	/**
	 * Destruction of the servlet. <br>
	 */
	@Override
	public void destroy() {
		super.destroy(); // Just puts "destroy" string in log
		// Put your code here
	}

	/**
	 * The doGet method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to get.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	@Override
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		response.setContentType("image/jpeg");
		response.setHeader("Pragma","No-cache");
		response.setHeader("Cache-Control","no-cache");
		response.setDateHeader("Expires", -10);
		
	    // 在内存中创建图象
	    int width=60, height=20;
	    BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

	    // 获取图形上下文
	    Graphics g = image.getGraphics();

	    //生成随机类
	    Random random = new Random();

	    // 设定背景色
	    g.setColor(getRandColor(200,250));
	    g.fillRect(0, 0, width, height);

	    //设定字体
	    g.setFont(new Font("Times New Roman",Font.PLAIN,18));

	    //画边框
	    //g.setColor(new Color());
	    //g.drawRect(0,0,width-1,height-1);


	    // 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
	    g.setColor(getRandColor(160,200));
	    for (int i=0;i<155;i++)
	    {
	     int x = random.nextInt(width);
	     int y = random.nextInt(height);
	            int xl = random.nextInt(12);
	            int yl = random.nextInt(12);
	     g.drawLine(x,y,x+xl,y+yl);
	    }

	    // 取随机产生的认证码(4位数字)
	    String sRand="";
	    for (int i=0;i<4;i++){
	        String rand=String.valueOf(random.nextInt(10));
	        sRand+=rand;
	        // 将认证码显示到图象中
	        g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));// 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
	        g.drawString(rand,13*i+6,16);
	    }

	    // 将认证码存入SESSION
	    
	    
	    String id = request.getParameter("id");
	    
	    if(id == null ){
	    	
	    	if(request.getRequestURL().indexOf("image1.jsp") > -1){
		    	request.getSession().setAttribute("userLogin",sRand);
		    }else if(request.getRequestURL().indexOf("image2.jsp")>-1){
                request.getSession().setAttribute("shengou",sRand);
            }
            else{
		    	request.getSession().setAttribute(SESSION4RAND,sRand);
		    }
	    	
	    }else if( "loginAjax".equals(id) ){
	    	
	    	request.getSession().setAttribute(SESSION_LOGINAJAX,sRand);
	    	
	    }
	    
	    // 图象生效
	    g.dispose();

	    // 输出图象到页面
	    //ImageIO.write(image, "JPEG", response.getOutputStream());
        JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(response.getOutputStream());
        try{
        encoder.encode(image);
        }catch(Exception e){
        	e.printStackTrace();
        }
	    //out.clear();
		//out = pageContext.pushBody();
	    
	    response.getOutputStream().close();
		//out.close();
	}

	/**
	 * The doPost method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to post.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	@Override
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

	}

	/**
	 * Initialization of the servlet. <br>
	 *
	 * @throws ServletException if an error occurs
	 */
	@Override
	public void init() throws ServletException {
		// Put your code here
	}
	
	private Color getRandColor(int fc,int bc){//给定范围获得随机颜色
        Random random = new Random();
        if(fc>255) fc=255;
        if(bc>255) bc=255;
        int r=fc+random.nextInt(bc-fc);
        int g=fc+random.nextInt(bc-fc);
        int b=fc+random.nextInt(bc-fc);
        return new Color(r,g,b);
    }

}
